Chromosomal cephalosporinase (AmpC), efflux pumps, and outer membrane protein expression levels among carbapenemase-negative Enterobacteriaceae isolates collected from European and Mediterranean countries during 2009 to 2011a

YrSite codeCountryOrganismPFGE resultRelative expressionb
2009081PolandE. cloacaeECL81C4.16782.6604.2330.006NT
2010063IsraelK. pneumoniaeKPN63F4.3692.2030.9701.2920.635
2010063IsraelK. pneumoniaeKPN63F1.8860.9530.7180.0110.612
2010081PolandK. pneumoniaeKPN81F1.5621.2160.4681.0330.736
2011063IsraelK. pneumoniaeKPN63E0.9991.1086.4780.0200.826
2011081PolandK. pneumoniaeKPN81B6.5871.8000.1930.0000.472
  • a One C. freundii isolate from Belgium was not analyzed because it failed in assays designed with available DNA sequences for the intrinsic genes tested.

  • b Expression was normalized against that of a housekeeping gene (rspL for E. cloacae and gyrA for K. pneumoniae) and compared to expression of E. cloacae ATCC 700323 and K. pneumoniae ATCC 13883. Expression values considered significant are underlined. NT, not tested.